Palladium-catalyzed C-P cross-coupling of allenic alcohols with H-phosphonates leading to 2-phosphinoyl-1,3-butadienes

The first facile, efficient, atom-economical and regioselective palladium-catalyzed direct C-P cross-coupling of unprotected allenic alcohols with H-phosphonates for the one-pot synthesis of structurally diverse multisubstituted 2-phosphinoyl-1,3-butadienes was developed. This strategy would enrich the allene chemistry and afford new scaffolds to construct complex molecular skeletons.

Simple entry into N-tert-butyl-iminophosphonamide rare-earth metal alkyl and chlorido complexes

New series of rare-earth metal dialkyls [(NPN^tBu)Ln(CH₂SiMe₃)₂(THF)_n] (Ln = Sc,n= 0 (2), Ln = Y,n= 1 (3)) and monoalkyls [(NPN^tBu)₂Ln(CH₂SiMe₃)] (Ln = Y (4), Nd (6), Sm (7)), [(NPN^tBu)₂Sc(THF)CH₃] (5) are achieved by protolysis of highly basic ligand Ph₂P(N-tBu)(NH-tBu) = (NPN^tBu)H (1). Further alkyl abstraction, alkyl/Cl exchange reactions and X-ray structure analyses of thus obtained new complexes are presented.

Ferrocenyl-phosphonium ionic liquids - synthesis, characterisation and electrochemistry

New unsymmetrically substituted ferrocenyl-phosphonium ionic liquids (ILs) [FcPR2R']NTf2 are synthesized by two or three step syntheses starting from ferrocene, Fc = (C5H5)Fe(C5H4); R = Me, (n)Bu, (n)Hex, Ph; R' = Me, (n)Pr, (n)Bu, Ph; NTf2 = N(SO2CF3)2. The selective synthesis of alkyl phosphines FcPR2via a Friedel-Crafts phosphorylation is highlighted as an alternative for the standard protocol commonly used for ferrocenyl arylphosphines involving lithiation of FcH followed by phosphorylation. The influence of the P-substituents on thermal stability, electrochemical potential, chemical shift, and UV-Vis absorption behavior of the ILs is studied. The phosphonium group acts both as an ionic tag and as an electron-withdrawing substituent directly bound at the Cp-ring position. Therefore the title compounds are attractive for further studies to use them as tunable redox mediators for (photo)electrochemical devices such as dye sensitized solar cells (DSSCs) or redox flow batteries.

Tetrahydropentalenyl-phosphazene constrained geometry complexes of rare-earth metal alkyls

A new sterically demanding rigid cyclopentadienyl chelate ligand facilitates NMR spectroscopic investigations and signal assignment of paramagnetic rare earth organometallics.

1,2-Dihydropentalenes from fulvenes by [6 + 2] cycloadditions with 1-isopropenylpyrrolidine

In situ generated acetone pyrrolidine enamine undergoes [6 + 2] cycloadditions with fulvenes to give 1,2-dihydropentalenes. This ring annulation method works particularly well with 6-monosubstituted fulvenes and is subject to steric hindrance at C-6 of the fulvene. On the basis of mechanistic studies, optimal conditions have been developed for a one-pot synthesis of 1,2-dihydropentalenes using catalytic amounts of pyrrolidine.